Recently, several golf balls exhibiting both high ball bounce resilience and a soft feel when hit have been proposed. One example of such golf balls is a multi-piece golf ball in which the ball is composed of a plurality of layers. Generally, in a multi-layered golf ball, especially in a golf gall that has three or more layers, a highly rigid core is covered with an intermediate layer that has relatively low rigidity, and the outer surface of the intermediate layer is covered with a hard cover. This arrangement aims to attain both high ball bounce resilience and a soft feel when hit by using the rigidity of the core and the softness of the intermediate layer. One example of such a multi-piece golf ball is disclosed in Japanese Examined Patent Publication No. 1991-52310.
However, golf balls having a conventional multi-layer structure do not always exhibit a satisfactorily soft feel when hit and further improvement in this soft feel is desired.
The properties required in golf balls include a long carry distance attributable to the above-mentioned high ball bounce resilience and to the spin; however, it is difficult to provide both properties in the same ball. Therefore, in commonly marketed golf balls, only one of the properties is generally enhanced. Because different properties are required in different types of golf balls, it is difficult to manufacture them using the same mold, thus increasing the number of manufacturing steps. From the view of reducing the cost of molds, the demand exists for sharing the same mold for manufacturing different types of golf balls.
The present invention aims to solve the above problems. The first object of the present invention is to provide multi-piece golf balls having a satisfactorily soft feel and high ball bounce resilience. The second object of the present invention is to provide a method for manufacturing multi-piece golf balls that can achieve both a long carry distance and satisfactory spin, which are inherently conflicting properties, using the same mold, and a mold for manufacturing such golf balls.